Harley-Davidson 1200 Sportster vs Triumph Thunderbird

The Triumph Thunderbird passes its MOT first time more often than the Harley-Davidson 1200 Sportster: 87.8% vs 79.1%, a 8.7-point lead.

MOT reliability, side by side

first-time pass rate, outright fail rate and tests analysed · 2005–2025

Metric	Harley-Davidson 1200 Sportster	Triumph Thunderbird
First-time pass rate	79.1%	87.8%
Outright fail rate	10.1%	6.2%
Median miles at test	13,693	13,106
MOT tests analysed	536	56,312
Most common failure	lighting and signalling	brakes

First-time outcomes on normal tests, 2005–2025. "Most common failure" is the component group with the most recorded defects on failed tests. Read pass rates against test counts: a smaller sample is noisier. Source: DVSA anonymised MOT results.

HARLEY-DAVIDSON 1200 SPORTSTER 79.1% pass · 536 tests TRIUMPH THUNDERBIRD 87.8% pass · 56.3k tests

See each bike's full report (trend, mileage curve, failure breakdown and rivals) on its own page.